1. Field of the Invention
The present invention relates to a superconducting cyclotron, particularly adapted for medical uses, which generates a beam of atomic particles or sub-particles, wherein the cyclotron and beam are rotatable in an arc around an object to be irradiated. In particular, the present invention relates to a cyclotron which is rotatable in an arc of about 180.degree. without spilling a liquified gas at near 0.degree. K. provided around magnetic pole coils for the cyclotron which renders them superconductive.
2. Prior Art
Various workers in the art have suggested that a relatively low power, e.g. about 25 to 75 MeV charged particle, superconducting, cyclotron which produces neutrons from the particles would be useful in medical treatment. Illustrative is an article by Hepburn et al, Int. J. Radiation Oncology Biol Phys. 3 387-391 (1977). The apparatus visualized as a concept by this publication includes a rotatable cyclotron with a support structure including a counterweight on a balance bar with a pivot pin at the fulcrum between the cyclotron and counterweight and with the pin rotatably attached to a mounting stand. The problem is that the design as conceived is not practical to construct. Liquid helium or other supercooled liquid gas presents a considerable handling problem when the cyclotron is rotated on such a support structure.
U.S. Pat. No. 3,868,522 shows a superconducting cyclotron with an air core rather than an iron core; however, the latter is preferred. Numerous superconducting cyclotron designs are known to the prior art.